It was by Paul Ysart.
I have a similar one which is neater although not quite as bright. Mine is shown at the top right of my "home page" and also in my selection of what I called "horizontal twist" weights:http://www.btinternet.com/~kevh.glass/pages/catalog/py-horizontal-twist.htm
It can also be seen in a larger photo at:http://www.kevh.clara.co.uk/exhib99/Modern/Scottish/YsartPaul/ModYsartPaulFiligree03.htm
I have seen others in the same pattern. Some were smaller and two were much larger.
As I had another committment in the Cambridge area that day, I decided to view the weight with the idea of leaving a bid. I was aware that there was interest, including from America, but I still expected a maximum hammer price of around the £500 mark (with premium etc, taking the full cost to the £600+ area).
On examination, I noted, in addition to the stated bruise to the base, two minor bruises and a chip to the dome, as well as a small lump of devitrification (frit) in the upper side interior. As far as I could tell, these were not mentioned in the auction description, which simply said "some light scratching"
On the basis of the bruises, chip and frit, I decided that I would not go for it. And anyway, with the known interest from many places, I suspected the eventual price would be quite a bit above my own maximum - even if it was in very good condition.
But £1,500 hammer price was, to my way of thinking, extremely high. But for those who bid more than £500, I imagine it was something they were happy to pay for as a example of a less-common pattern and a weight of magnum size.
Oh, one other thing ... my example is exactly 11 cm diameter. When I handled the Cheffins one, I did not feel it was really 12 cm. But it may be just that mine has a higher (more rounded) dome and therefore the Cheffins one felt lighter, so I was fooled into thinking it was not as big as stated. I did not have a measure with me, so I did not check it.
By the way ...
... on the other board (which you don't visit often enough!!).
Which "other board" is this? Are you meaning the one that, I think, was set up some time ago for the "London Glassaholics group"? If so, because I was not part of that Group, I never joined that Board.